1. Field of the Invention
The present invention relates to improvement of a tremolo arm portion to be mounted on a tremolo unit for vibrato performance in an electric guitar, and more specifically to improvement to perform height adjustment and rotational torque adjustment of the tremolo arm.
2. Description of the Prior Art
In electric guitars in general, a tremolo unit is installed at body side and one end of a string is hooked to the tremolo unit, and on the other hand a peg is installed at neck side and other end of the string is wound on the peg. The tremolo unit has front end portion pivotally installed to the body and is movable in the vertical direction. A tremolo arm is mounted on the tremolo unit and is operated to rotate the tremolo unit downward so as to perform the up action of tone by increasing tension of strings, or to rotate it upward so as to perform the down action of tone by decreasing the tension of the strings, and this action is repeated in a short time thus the vibrato performance is feasible. The tremolo arm is usually engaged rotatably with the tremolo unit, and height of the mounting position of the tremolo arm and strength of its rotational torque can be adjusted according to the tightening state of the threaded portion corresponding to the music program and preference of the player. More specifically, a male screw portion threaded on base portion of the tremolo arm is threadedly engaged with a mounting hole (tapped hole) opened to the tremolo arm so that the height adjustment and the rotational torque adjustment can be performed.
In a tremolo arm in the prior art as above described, the male screw portion is threadedly engaged with the mounting hole (tapped hole) thereby the height adjustment and the rotational torque adjustment can be performed. In this case, however, conflict occurs between following states:
(1) That when the male screw portion is rotated in the loosening direction and the mounting position is set high, the rotational torque of the tremolo arm becomes small, and
(2) that when the male screw portion is rotated strongly in the tightening direction (when the tightening state of the threaded portion is made firm) in order that the rotational torque of the tremolo arm is set large, height of the mounting position of the tremolo arm becomes low.